Review: Canon EF 600mm f/4.0 L IS III and Extender EF 1.4x III

by John Gerlach – www.gerlachnaturephoto.com

Both the 600mm lens and the extender are the latest versions as of this writing on

April 1, 2019. Despite the date, this is no April Fool’s joke. I expected a lot from

this lens combination and needed to test it by photographing animals in field

conditions. Fortunately, there were plenty of ducks in Indiana at the Perrin Family

Park in Jeffersonville during March. They were extremely approachable. Actually,

the ducks found me approachable as access to the pond is limited except at the

waterfowl feeding station where ducks approach visitors for handouts. For $.25,

you can buy nutritious food for the wild ducks that frequent the site. During a few

visits to this park, I shot at least 6000 images with the 600mm lens by itself or with

the 1.4x extender attached. Here are some image results and my opinion on the

gear.

Figure 1 Northern Shoveler near the waterfowl feeding site

When the 600mm lens arrived, I was delighted to open the package and learn

more about it. The first thing I did was look it over carefully to check for any

damage and to admire it a little – okay, a lot. Then I read the small instruction

book for the lens. I have used the Canon 500mm for thirty years, and the 800mm

for a decade, so this lens is like them in many ways. That means the usual buttons

and switches built-in to the lens are present and everything is already familiar to

me.

Although I typically use manual focus with live-view for close-ups and landscapes, I

nearly always use autofocus with my long lenses when photographing wildlife as I

need the speed and focus tracking ability to stay locked on to active wildlife. Since

I know autofocus is rarely perfectly accurate with any lens/camera combination,

the first thing I photographed was a test chart to run an AF microadjustment test.

I cover how I do this in detail on my blog at my website.

(www.gerlachnaturephoto.com) After running the AF microadjustment test for the

Canon 600mm by itself, and with the 1.4x extender attached, I found I needed to

set these values. Amazingly, the 600mm without the extender did best at only a -1

AF microadjustment setting, and that isn’t much. More significantly, with the 1.4x

extender attached to the 600mm, I needed a +5 setting to correct for a small front-

focusing problem. The +5 correction makes the lens focus a little farther away,

and a minus correction of -1 makes the lens focus a little closer to the

photographer. Keep in mind neither adjustment is huge, and most photographers

might think their lens is focusing perfectly if they made no AF microadjustment

correction. But for critical sharpness, using these values is necessary with my gear.

These values are necessary for my gear, but other gear might easily be entirely

different.

Figure 2 A female wood duck with the 600mm lens and 1.4x converter

Why the 600mm when I have the 800mm?

For decades I photographed wildlife with several versions of the Canon 500mm

lens. I have always wanted more reach to photograph wildlife at greater distances.

A decade ago I sold my 500mm lens and bought the Canon EF 800mm f/5.6 L IS

USM. Instantly, I had a lot more lens to bring distant wildlife optically closer to fill

the frame with subject. I shot thousands of images with the 800mm that please

me over the years. If only I had begun using the 800mm lens earlier in my career.

The long lens is such a game-changer for me that I will continue to use long lenses

for as long as I can. Bottom line: the 800mm lens is a tremendous addition to my

camera gear.

Figure 3 Northern Shoveler

Although the 800mm lens is superb for wildlife photography, I continually seek

better ways to photograph wildlife. The 600mm lens with the use of a 1.4x

converter became an appealing combination that I had to have. I was eager to try

it out as it offered several advantages.

• The 800mm f/5.6 lens is one stop slower than the 600mm f/4 lens. When I

need more shutter speed and wish to keep the ISO down as much as

possible, being able to open the lens up to f/4, rather than f/5.6, drops the

ISO by one stop. In other words, if I had to use ISO 4000 with the

800mm/f/5.6 lens when set to f/5.6, I could use ISO 2000 with the one-

stop faster 600mm f/4.0 lens.

• Of course, the lens speed factor equals out when the 1.4x extender is

added to the 600mm lens, as it turns the lens into an 840mm f/5.6 lens.

Though, the lens speeds are now the same, notice I get a little more focal

length of 840mm with the 600mm/1.4x combo than the 800mm lens by

itself. In wildlife photography, more focal length is frequently beneficial as

you can be farther from the subject at a safe distance while letting the

animal behave naturally.

• Another key plus for the 600mm lens is the close-focusing ability. The

600mm lens focuses as close at 13.78 feet or 4.2 meters, while the 800mm

only focuses as close as 19.69 feet or 6 meters. The ability to focus close is

incredibly important for small birds, mammals, lizards, and other wildlife.

Sure, you can use extension tubes to make the lens focus closer (such as

the Canon 25mm tube), but it is cumbersome to use, slows down the lens

speed, and prevents you from focusing to infinity should you suddenly

need to do that.

• The Canon 600mm f/4 III lens is lighter at 6.7 pounds than both the old

version of the 600mm and the 9.9 pound Canon 800mm lens. Carrying a

big telephoto lens that is lighter is always an advantage, especially for long

distances.

Lens Minimum Focus Distance Weight

Canon 500mm f/4 12.14 feet 7 pounds

Canon 600mm f/4 II 14.76 feet 8.6 pounds

Canon 600mm f/4 III 13.78 feet 6.7 pounds

Canon 800mm f/5.6 19.69 feet 9.9 pounds

Notice the Canon 600mm f/4 III is the lightest lens of this group, even lighter than

the 500mm lens. Only the 500mm lens focuses closer at 12.14 feet than the 13.78

feet of the 600mm. True, I wish the 600mm focused a little closer for small birds

like warblers, but 13.78 feet is still is quite close-focusing for a long telephoto lens.

Figure 4 Female Northern Shoveler

My Photo Experiences with the Canon 600mm f/4 III Lens

After AF microadjusting the Canon 600mm f/4 III lens and setting a -1 AF

microadjustment correction for the lens by itself, and a +5 when the lens is used

with the 1.4x extender, I visited a local pond where they have a designated duck

feeding station in southern Indiana. Loads of Northern Shovelers and a couple of

wood ducks approached me to within ten yards – hoping for food handouts.

Although I did not have any “duck food,” plenty of other park visitors did. Due to

park rules, park visitors are restricted to a viewing platform slightly above the

pond. I would prefer to sit on the ground to photograph for the lower angle that

position provides, but that was not allowed. So, to make the best of things, I

mounted the 1.4x extender on my camera and then the lens to that to make my

focal length 840mm. This let me make large images of the ducks when they were

much further out in the pond where the shooting angle is more favorable, rather

than shoot down on the ducks from a closer distance.

Figure 5 Drake Wood Duck calling

At first, I set my exposure manually by using the blinkies method I have used very

successfully for the past several years and perhaps ½ million images. I shoot only

RAW files and the in-camera exposure aids of the histogram and highlight alert

(blinkies) are both based on an embedded JPEG in the RAW file. While many

believe blinkies show areas of overexposure, in truth the RAW data is not

overexposed when the first blinkies appear. Therefore, I simply set a manual

exposure using the exposure scale in the viewfinder to get the exposure close,

shoot the image, check for blinkies, and when I get the first blinkies to appear, I

use that for my exposure going forward unless the ambient light levels change. As

I photograph, I constantly monitor the blinkies when I playback the images. If

more blinkies appear, I subtract light by increasing the shutter speed (usually) or I

stop down a little more if more depth of field is desirable. If I stop getting blinkies,

then I add a little more light by slowing the shutter speed, opening the aperture, or

perhaps some of both.

I did change my exposure late in the afternoon when shadows were cast on the

water. A duck in late afternoon sunshine is swimming in much brighter light than

one that swims into the shadows. Though manual exposure has enormous

benefits over all autoexposure methods, when ambient light changes quickly, then

autoexposure is the way to go (even this dedicated manual exposure shooter

admits that). When ducks paddle into the sunshine for a minute or two and then

into the shadowy water, I switch to Auto ISO with manual aperture and shutter

speed and exposure compensation. The beauty of auto ISO is the desired aperture

and shutter speed stay the same, and the camera’s ISO varies to correct for

changes in ambient light levels.

Figure 6 Drake Northern Shoveler in the shade!

Big lenses can be handheld for short time periods but photographing swimming

ducks requires staying on them optically for long time periods to catch special

action shots. Often, I am peering through my viewfinder while tracking the duck

for ten minutes or more, and there is no way I can hold the lens that long. It is

best to mount the tripod collar of the lens to a Wimberley gimbal head. When

both balance adjustments are done, the lens will stay in perfect balance wherever

you point it without locking the head up. This enables tracking wildlife motion

efficiently.

Autofocus offers many options and I go back and forth between many of them. I

am a big believer in back-button focus where the autofocus is assigned to a button

on the camera’s rear. In my case with the Canon 1DX Mark II and 5D Mark IV, I

assign back-button focus to both the AF-On button and the * button. I also assign

different focus patterns to the two designated buttons that control autofocus. The

AF-On button has single-point AF assigned to it, and the * button has a group of

five active AF points assigned to it. If I am having trouble keeping a single AF point

on the duck’s face with the AF-On button, I then press the * button to get a larger

group of active AF points.

With back-button focus, I always set the focus to continuous autofocus where it

tracks moving subjects if the active AF point or points is on the subject and the

back-button is depressed. Letting up on the back-button locks autofocus, and that

is useful when the subject is still.

Since interesting behavior is often fleeting, I always set my camera to the fastest

shooting speed – currently 14 images per second with the Canon 1DX Mark II.

What is interesting behavior? When a duck gets up high on the pond to flap its

wings, or takes a splashy bath, that is fun behavior to photograph.

Figure 7 Northern Shoveler drying its wings

When the ducks are steadily swimming, even if slowly, then I find it works best for

me to assign the focus control to the shutter button. Then as I compose the duck, I

notice what AF point coincides with the duck’s face, quickly move the joy button

on the back of the camera to select the AF point that coincides to the face and

shoot away. Of course, as the composition changes, I continually must move the

active AF point around to coincide with the face.

When I examine my images to find the ones I wish to keep, I first look at the

overall composition and scroll through my images quickly using Canon’s DPP4

software (always the latest version). I shoot a lot of images of a slowly swimming

duck. Though, I am careful, I sometimes cut the tail off the duck in the

composition and that is an immediate reject. If the duck blinks and the eye is only

partially open, that is a reject. Typically, I go through several good images, but

then once catches my attention. I enlarge the head to 100% to check for

sharpness. If the pose is pleasing and the head is sharp, I give it a rating. In this

way, I may view 1000 images per hour and check perhaps 45 images. Once I am

through the folder, I can select all the images I did not rate and delete them. Then

I return to the keepers and try to cut them down a little until ending up with 25 or

fewer images.

My strategy is to shoot a lot of good images but hope for a few exceptional images.

By shooting a lot of images, there is a greater chance of photographing exceptional

action. Often, ducks do things quickly. If you see the duck rise and flap its wings,

you can’t photograph it if you observe them doing that and then try to photograph

it. Normally neat behavior lasts a second or two at best. You must be shooting

when action happens – or you are always too late.

Figure 8 Canada goose with the Canon 1DX Mark II, 600mm, and 1.4x converter

Keep the Duck Level

My cameras offer a level on the LCD, and another one displayed in the viewfinder.

Since I am peering through the viewfinder when photographing, the level on the

LCD is useless at that point, so I monitor the level I see in the viewfinder in real

time as I shoot and compose the duck. Though, I sometimes am off, I find it is easy

to use the viewfinder level to keep the water and duck level.

Conclusion

I feel the Canon 600mm f/4 III lens with the Canon 1.4x converter is the best long

lens combination I have used in my 45-year career. This combination is awesome!

It isn’t cheap, but you get what you pay for in this case. Go ahead and splurge, you

will be glad you did.

Figure 9 While walking to the duck pond, this American Robin posed nicely for me.

Figure 10 The reach of the 600mm/1.4x extender combo gave me an extremely low angle to this Canada goose that was not intimidated by me at all.

Figure 11 The close-focusing ability of the 600mm f/4 III lens makes it easy to capture large images of small subjects like this Tufted Titmouse.